In exposure systems in lithography, the temperature of the individual elements of such a device is a critical parameter. Above all, the temperature of the substrate and the mask should be as constant as possible. The change in the temperature of the respective elements of the device leads to a change in the dimensions of the elements. This might lead to errors during the exposure of a substrate. The temperature of the substrate can be well adjusted and controlled through the substrate support. It is desirable that the dimensions of the mask remain constant when the substrate is changed and also between the individual exposure phases. However, exposure of the substrates heats the mask.
EP 0 940 718 A2 teaches to cool the mask by means of air. However, air cooling or air heating normally changes the temperature of the mask only slowly. The speed at which the temperature of the mask can be changed depends decisively on the thermal gradient between mask and air as well as on the air conduction. The higher the thermal gradient and the stronger the heat flow, the greater the temperature change of the mask. Air cooling with normal parameters, however, cannot react quickly enough to the temperature change and thus the change in the mask dimensions.
US 2004/0053169 A1 describes a method for minimizing the thermal gradient in a mask used in extreme ultraviolet lithography and which is arranged at a relatively large distance from the wafer to be exposed and which is heated by a heat source radiating from the front and cooled by a cooling device facing away from the wafer and contacting the rear of the mask.
U.S. Pat. No. 6,342,941 B1 describes a projection exposure method in which the mask is preheated before exposure up to a thermal expansion saturation point on the basis of pre-calculated data.
Further prior art is known from US 2003/0179354 A1, U.S. Pat. No. 5,593,800 A and DE 28 44 368 A1.